Climate change isn’t just making the world warmer. It’s also changing when and how much rain falls. That leaves more corn farmers at risk of facing drought during part of the growing season.
“A severe drought during the corn reproductive stage can cause a complete crop failure,” Ranadheer Vennam, a graduate student in the Mississippi State University Plant and Soil Sciences Department, said in a university news release. “So understanding corn responses to drought and managing accordingly is critical for successful corn production.”
Vennam and his laboratory group looked at how sensitive corn flowering is to drought and the impacts it has for farmers. Corn flowering is complex. Each individual ovule produces a long silk, which must capture pollen from the tassels above the plant to produce a kernel.
“Successful reproduction in corn is all about timing,” said Raju Bheemanahalli, an assistant research professor in agronomy at Mississippi State. “It takes less than two weeks for corn to pollinate, which is extremely sensitive to stressors, including drought.”
Vennam’s team exposed corn plants to various levels of drought during flowering. During the two-week flowering period, the researchers reduced the amount of water each plant received. In the most extreme test, the plants received just 20% of the amount of water they needed.
The researchers measured how much the silks grew every day as well as final yield and key quality traits of the kernels. They also tracked aspects of plant growth such as leaf-chlorophyll content.
When exposed to severe drought, the ears of corn produced much less silk biomass than healthy ears. The number of silks also was about one-third less. Yield decreased by 90% in the severe drought treatment. That was the result of a reduction in number of kernels and how much each kernel weighed.
The researchers also tested a month-long drought stress after flowering was done. Even though that drought lasted more than twice as long, yield wasn’t affected as much.
“That illustrates the sensitivity of the reproductive stage to drought stress, its timing and how stress affects corn production,” Bheemanahalli said.